How To Build and Fit the Augmented Reality Projector of a PUMA Open Source 3D Printed Microscope
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- Опубликовано: 6 сен 2024
- The AR projector overlays a programmable heads-up-display (HUD) onto the live optical view down the microscope so you can implement AR microscopy. Details of how to implement AR microscopy were given in a separate video ( • Augmented Reality Micr... ). This video shows you how to actually build the AR projector and fit it to the microscope.
PUMA is a DIY open source portable 3D printed microscope with fluorescence, polarisation, dark ground, phase contrast, epi-illumination and other advanced features.
CONTENTS
========
00:08 Overview of Augmented Reality Microscopy
00:35 Principles of the AR Projector
02:10 Magnification of Microscope Objectives
05:19 Eyepiece Field of View - the Field Number
06:34 The AR Projector as a 0.8x Objective Lens
08:48 Features of the AR Projector
10:03 Using the AR Projector to view Microscope Slides
11:44 Customising the TFT Backlight Brightness - Danger!
12:14 How to Build the AR Projector
21:21 Updates to the AR Stay Clip and Thumbwheel
23:03 Attaching the AR Projector to the Microscope
24:46 Collimating and Focussing the AR Projector
29:52 Fitting the TFT Light Shield
30:23 Intro to the Software Manual
SUPPORT PUMA
============
PUMA is an open source microscopy project. You can help support the project by:
1. Become a Patron: / pumamicroscope
2. Donate via PayPal: www.paypal.com...
3. Simply subscribing to this RUclips channel, like, comment and share these videos.
4. Spread the word - post the news about PUMA and link to this RUclips channel on your social media sites and any other outreach method (tell your friends, colleagues, students or teachers and lecturers about PUMA, for example).
5. Consider purchasing your optics and related supplies from our affiliated online optics store, OptArc.co.uk ( www.optarc.co.uk/ )
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PARTS AND TOOLS
===============
For the latest details see the 'Bill_of_Materials' on the PUMA GitHub page ( github.com/Tad... ). The following notes explain the changes made while preparing this video. These changes have been incorporated into the Bill of Materials on the GitHub page just prior to release of this video.
3D Printed Models Updated for this Video
-------------------------------------------------------
AR_Module:
TFT_Drawtube_F - modified to give more upwards adjustment to compensate for the image shift of the beam splitter for the transmitted stream.
Slide_mount - new. A mount for a standard 25x75mm slide to use the AR projector as a general 0.8x objective.
Cx_collar - modified to have a more reliable locking mechanism.
Cx_Lens_holder - modified to work with the updated Cx_collar.
Clip_lock - abolished (the new clip design incorporates it)
Clip - modified to include the clip lock as one solid ring and printed on its side for extra strength. This uses the 'flats' Cura profile with normal supports 'touching baseplate only'
Light_block_filter - new. This is an opaque disc 17.5 mm in diameter for use as a light blocking filter for use in the standard PUMA filter trays so you can easily block light from the main objective port when using the AR projector as a specimen projection objective.
Monocular:
Projector_cone - new. Ocular head projector cone for demonstrating primary objective image
Aperture_46mm - new. Fits on top of projector cone and designed to take a tracing paper disc as a projection screen (glued in place).
Aperture_20mm - new. Fits on top of projector cone and designed to show the 20 mm diam. FOV of an ocular with field number 20.
Non-Printed Parts and Tools
---------------------------
Changes of note that have been introduced with this video are that I now recommend a 14 mm long M4 screw (not 12 mm as before) to use in the front of the focus platform (to act as a post for the AR clip stay thumbwheel).
I also introduce the use of the standard condenser gripper thumbwheel model modified to be used as a locknut for the AR stay mechanism so this will require an extra 3 mm long M4 nut.
FOR FURTHER INFORMATION
=======================
1. Open access write-up about PUMA on the FreeCAD blog:
blog.freecad.o...
2. The official PUMA GitHub page where you can download the specs and source files to build or customise your own PUMA system:
github.com/Tad...
3. The scientific peer reviewed publication on PUMA that was published in 2021 in the Journal of Microscopy (a journal of the Royal Microscopical Society) available here:
pubmed.ncbi.nl...
onlinelibrary....
Thanks for your interest in the PUMA microscope system.
PJT 23/04/22
Hi Paul, I was wondering if you had any advice regarding the 26mmx-55.6mm achromatic doublet. I am having issues sourcing this lens and the seller said it wasn't being manufactured at this time. So I was wondering if extracting one from a cheap achromatic Barlow lens would work. I have a feeling the diameter of the lens would be close to 26mm. As for the focal length, I'd probably have to search the internet to figure out the focal length of x2, x3 and x5 barlows.
Thanks.
Hello. I agree with your general idea. Of course any alternative would likely need some changes to the 3DP models in diameter and lengths and you would need to calculate those (it is one of the benefits of having an open source parametric DIY 3DP microscope). If you do a search on AE for 'minifying lens' you will see some possible alternatives like this:
www.aliexpress.com/item/4001005707914.html
or this:
www.aliexpress.com/item/4000970055079.html
and then there's Edmund optics:
www.edmundoptics.co.uk/p/25mm-dia-x50mm-fl-vis-0deg-coated-double-concave-lens/8125/
and when I first built the AR projector prototype I used this lens:
www.aliexpress.com/item/1005002756999921.html
It is bigger (42 mm diam) with smaller focal length (-40) but worked with appropriate projector tube adjustments (so the other alternatives above should be even better).
The issue with all examples above is they are not corrected for spherical and chroma so the image will show some distortion and colour separation.
You may also find something suitable in taking apart those cheap 'clip-on' wide angle lenses for smart phones.
I may revisit this when I have more practical experience myself at building an AR projector with an alternative lens. All the best.
Hi, I have been wondering if its possible to control ar hud with external TFT touchscreen. I want to show phototaxis of euglena to students, and my plan was to use external TFT touchscreen to project touch-based interactions of students as light beams to euglena gracilis, then see reactions of euglena gracilis based on those touch interactions in screen. Is it possible? Sorry if that sounds confusing, english is not my mother tongue.
Hello. Sure - what you have said should be possible. There are a number of ways of achieving it. Let's assume you have built the AR Projector optical tube, then:
One method is to use a smart phone or tablet in place of the standard TFT screen - for example holding the phone at the right position in front of the stand in the same way I held up the slide of an eyeball in my video on 'Photology 5' at about time point 00:10:12 ( ruclips.net/video/u_0xczp4210/видео.html ) with some drapes to shield from outside light. Then simply use this phone or tablet as a wireless screen 'mirror' or 'screencast' device to receive the video signal from the phone or tablet your students are holding.
The other option is to use the standard TFT screen AR projector but you will need to write the interface yourself because that is not a standard feature of the current PUMA Control software - and you may also need to use a more powerful Arduino than the standard 'nano' version I use in my demos here (perhaps like the Arduino Mega). You would then connect the tablet or phone to the Arduino with your own software painting to the TFT screen in response to your students touch-movements on the tablet / phone.
I haven't done any of this so can't guarantee it will work but those are the ways I would approach it.
How long are the 4 Machine Screws that hold the TFT to the Mounting Plate?
I don't see those on your Bill of Materials. Do you have an updated BOM maybe one with quantities and total pieces of Fasteners?
It sure would be helpful to know exactly the number of screws in each length are needed.
Also I am wondering how you use the SLM and the AR Projector at the same time?
Thanks, I can see you put a great deal of thought into the design!
Hello, the M2 bolts are 8 mm long and you need 4 of them. I just checked the BoM and the information is there (it is listed in the 'MD_AR_Projector' module worksheet in the list of 'non-printed-parts' as 'M2_Allen_Bolt_Socket_Cap_DIN912_8mm_long' and the quantity is given as 4).
The only way to get AR Proj and SLM to work simultaneously (and independently) is to have two separate TFT drivers - so, for example, either two PCCs or use a PCC for one and a separate source (e.g. your PC or a modified PCC) for the other (I say 'modified' PCC because clearly you don't need the lamp and motor circuitry if you are just controlling the SLM). I hope it all works out.
@@PUMAMicroscope , Oh WOW, Thank You yes I see the parts now. I was looking at the 2nd tab on the excel spreadsheet with the web links but now I see all the other tabs. My eyesight is not that great these days.
I have some other questions because I am trying to get together my list of stuff I will order to build this, I when I was looking for the 25mm Dia.x100Focal length infinity Lens for the Advanced Filter just above the Beam Splitter and at AliEx. it says that it is no longer available. So I have a few questions,
1. is that lens only used in conjunction with Infinity Objective Lenses? And if I don't use the infinity lens in the Advanced Filter do only the "Plan" style Objectives give a perfect clear image?
And is there a place you can recommend to get the lens for the advanced filter?
So I am wondering if it is best to get the Plan Objectives or the ones with the infinity symbol on them? I will appreciate any advice you have about that.
Also I have a strange question, My eyeballs are very Myopic and I also have a extremely Severe Astigmatism so My question is do you think there is a slim chance I can find Anamorphic Lenses for the Eye Piece Lens of the Microscope?
And I really wish there is a way to design a Turret into the Focal Plate but even so it is a awesome Microscope, I salute you.
I am gonna build it with all the bells and whistles.
I know a little about programming, electronics and engineering(I used to work in engineering), I looked into the TFT's with the Nano and multiple TFT's can be wired in Parallel but they will Display the exact same thing BUT there is a Way to use a IC2 Multiplexer Chip PW548A with the Nano to address up to 8 devices independently. I watched a couple kids use that small chip specifically with the Nano and 4-ST7789 Displays presenting independently. So, I think I will use this feature in my project because I wanna use the SLM & AR Projector at the same time.
I think it will fit inside the PCC.
I also I plan on trying to make it as Wireless as possible and maybe even using small stepper motors for the XY Stage maybe.
Something else I came across that you may or may not be aware of is that the Nano using a Atmega328 Flash RAM chip wastes about 1500 bytes of the Flash Memory when the old 2.0kb Bootloader is updated to the 0.5kb Optiboot_Atmega328. With Nano the Maximum Upload size is Factory set to 30720 with all bootloaders so with the smaller bootloader(0.5kb) there is about 1500 wasted bytes. This can be Optimized to use the Full 32256 bytes of Flash Memory when using the New Bootloader.
In order to Correct this and get access to Full 32256 Memory you change the Line Code for avr--->(version)--->boards.txt file...
high_fuses=0xDE
instead of the old 0xDA
Other suggestions I have is a simple small hole in the top of the PCC to access the Current Pot on the Buck Converter with a small screwdriver instead of the knob at the top and simple. And simple clear plastic sheets over the slots glued from the inside to view the internal LED's of the PCC is another option instead of printing clear plastic optical wave guides but I like your idea of just keeping it open for more ventilation.
Thanks a lot for your time and effort, it is greatly appreciated!
Thanks for your interest - you are doing great stuff and I hope you publish it somewhere on your social media or YT.
Regarding the infinity stuff - my advice is do NOT use the 100 mm lens and AVOID infinity objectives (the ones with the infinity symbol on them). The 100 mm lens is exclusively only for use with infinity objective and must not be used with fixed tube length (i.e. non-infinity) objectives. Note - infinity is nothing to do with Plan or not Plan - that is a separate issue. You can have Plan objectives that are infinity corrected and Plan objective that are fixed tube length. The objectives you need are the 160 mm tube length objective - they will have 160 printed on the barrel. Plan ones are better for flat field viewing. Your eyeballs shouldn't make a difference provided you use your glasses when looking down the tube and use a high eyepoint ocular lens (eyepiece).
The reason I say avoid infinity objectives and the 100 mm lens is because I only made the 100 mm / infinity option as a concession to allow use of infinity optics for those who happen to have them lying around but the 100 mm focal length is too short for optimum correction of the image and you end up with a curved field of view. One day I may make a more dedicated infinity module for better use of infinity optics.
All the other electronic stuff you talk about is fine - I didn't want to get into such details for the average person might be put off by it but clearly you have the knowledge to do it so that would be great if you get it to work. Please post your results somewhere. All the best.
@@PUMAMicroscope , oh o.k Thanks! so the Plan just means the Planar meaning the lenses are flat on one side and either convex or concave on the other. o.k. I think I get it now, this is real optical Physics as opposed to the thing the eye doctors do😉 I don't like the Flat lenses on my eyeglasses, I think because my face and and retina have a curvature. I normally don't look thru my glasses at objects closer than about 20 cm. I have never used my glasses while looking thru a microscope, even in school, because it hurts my eyes. I have done many tests on myself and at Close Range I only need the Cylinder correction because of the Astigmatism in my eye.
That's why I am thinking about how I can put an Anamorphic Cylindrical lens either right before or right after the eyepiece of the Microscope. if I put a Cylinder Lens in the Advanced Filter then I think I can also use a Custom CinemaScope type image Capture maybe with a Camera on the Triocular and in that way get a much higher Resolution Photo and Video image after Post Processing but it would be a Custom Aspect Ratio that I would have to correct back to a Perfect Circle in Post Processing.
I was on the edge of my seat when you were talking about Pupil Distance in the Binocular eye Piece Video, you truly know this stuff and you have considered everything in the Design, Thank You so much!
Yes I will post my results here on yt and keep in contact with you.
Thanks Again^!!^
The 'Plan' refers to focal plane flatness in the final image - not glass flatness. It means that, with a Plan objective, the centre of the field of view will be in focus at the same time as the periphery of the field of view. With cheaper non-plan corrected lenses you can only get the centre or the periphery in focus at any one time - never both at once.
Your glasses have the correct cylinder for your eye. I would think that a cinematic anamorph would probably over-correct for you. I have glasses too and it is much better for me to look through a high eyepoint eyepiece lens with my glasses on - but the eyepiece lens must have a high eyepoint (sometimes called high 'eye relief') or this won't work because you won't be able to get your eye close enough to the eyepiece to see the whole field of view properly because the glasses get in the way. High eyepoint eyepieces usually have a symbol of a little pair of glasses printed onto the barrel of the eyepiece. Don't confuse this with 'wide field' - that is completely different.
Hi, I really like what you've done here. Can you give any generic advice to adapting this for regular compound microscopes to be attached to their trinocular ports? Eg a Leitz laborlux please?
Hello. The optical principles are as described in the videos - you need to project an image of your computer screen to be focussed on the same plane as the ocular lenses' focal plane. Achieving this with other microscopes can be a problem because their 'trinocular' ports point down to the specimen so if you shine an image down there then part of your projected computer screen image will also go down onto the specimen and may cause unwanted back-reflections. The PUMA arrangement allows the image of the TFT screen that gets past the beam-splitter to go horizontally and be either absorbed by a light sink or used in the PUMA trinoculular port which is lateral (at 90 degrees) to the specimen. So this image does not spoil the specimen.
I suppose you might be able to achieve this on a standard microscope by using a double header-type splitter port or a port that would otherwise be used for a pointer but the details of getting the projection and zoom right might be tricky - I have not tried.
@@PUMAMicroscope Thank you for your comments. I thought that my trinocular head had a built in beam-splitter but after reading your comment and checking this might not be so. I will have to check in detail. I suppose the alternative is to adapt an attachment in between the binocular/monocular eyepiece similar to the puma so I can include a beam-splitter into it (you use a SSM instead of a prism here it seems). My very loose understanding of optics (from school many years ago) suggests that I will need to add a focusing lens to this extension attachment to account for the extra distance made (as the microscope is a 160mm one as it is not infinity corrected). Would this be a correct general outline of the task at hand? Thus in this case I would (if you allow me to) adapt your Puma system to include an additional focusing lens and also adapt connectors at both ends to join this to my microscope.
Would this be OK with you. I would also appreciate any additional pointers you could give. Thank you!
@@letshin Your trinocular head does indeed have a beam splitter in it, just not in an optimal configuration for use as a AR projector set up. Whatever method you try, you will need to use lenses to ensure a projected image of your TFT screen (or smartphone screen if that is what you are going to use instead) is focussed onto the focal plane of the oculars and avoid getting light from the screen to go down onto your specimen (ideally).
@@PUMAMicroscope Thanks, I think I would like to start off by making the PUMA AR projector and the above stage optics to figure out what I need to do to adapt this for my own use. I checked the Github and looking through the 3d printing guide it seems I will need the binocular head (BN_) files as well as the AR projector (AR_) files. Will I need the filterblock module as well? Is there a document/decision tree that relates how the different modules link together?
Edit: The possible configurations are at the end of the BoM Excel file so I'll refer to this instead. I've ordered the required mirror and beam splitters from these (I have spare eyepieces and objectives) so will see how this goes. Thanks!
@@letshin You do NOT need the binocular head for the AR projector. You DO need the advanced filter block.
Some people have told me they have had difficulties getting the concave lens for the AR projector. It would be interesting to know if you can get it.
😃😃
That is a Tactical Microscope 🤪
@@arctictimberwolf 😳😳 how you saw my comments it's two days ago
@@arctictimberwolf 😘😘
Great and interesting works!
But honestly, I see that the precise and expensive objective lens is mounted on a loose and lots of burr and dust 3D printed mounting, I have screamed internally all the time :)
I think I can try to modify your design with machined parts and Thorlabs tube system, when I got time :D
No need for dust and burrs, etc. - the build quality depends on the care taken by the builder - so for sure it *could* be as you say but that is up to the individual builder. Yes - you could build a much better microscope from engineered metal and Thorlabs stuff but it would be out of reach for most people to do this - technically and cost wise. The PUMA is made to make high end customisable microscopy available to more people on low budgets with only a 3D printer (or access to an online 3D print service) for the special parts. If I were building with metal I would use quite a different design for many parts.